Various protocols may be used to enable a client device to access and retrieve e-mail or other message data from a remote server. For example, post office protocol (POP), currently in version 3 known as “POP3” and as defined in Internet Engineering Task Force (IETF) Request for Comments (RFC) 1939, and internet message access protocol (IMAP), currently in version 4 revision 1 (IMAP4rev1) as defined in IETF RFC 3501, are application-layer Internet standard protocols that may be used by an e-mail client application to retrieve e-mail messages and related data from a remote mail server. In general, these e-mail protocols are designed to be simple, to enable efficient access and retrieval of the e-mail data to minimize server-side processing and bandwidth usage. However, the simplicity of the e-mail protocols may raise potential security concerns. For example, these e-mail protocols typically do not include provisions for inspections to deter unauthorized use of passwords and account data.